(1) Field of the Invention
The present invention relates to a method for producing roux and more particularly to a method for producing roux, such as roux for curry and stew, by using a twin-screw extruder.
(2) Prior Art
Roux, such as for curry, stew and white sauce, has been produced by heating and kneading a starting material mainly comprised of wheat flour, fats and oils and seasonings and has an inherent color and texture due to the fusion of the wheat flour and the fats and oils used. Moreover, the seasonings impart pleasing taste and flavor to the roux, so that roux has been widely used as a basic material for foods or to impart color and/or taste to cooked foods.
Generally, it has been known that characteristic properties of roux such as color, taste and flavor are greatly influenced by the heat condition during the production thereof. Particularly, in order to obtain roux having rich taste and flavor, the roux must be uniformly heated at an elevated temperature. Nevertheless, the heating of roux has conventionally been carried out by using a directly heated roasting kettle or a steam heated roasting kettle and therefore, there are various problems to be solved.
The starting material must be sufficiently and uniformly heated at an elevated temperature in order to obtain roux having good taste and flavor by using such an kettle. However, the heating efficiency of such an kettle is inferior and as a result, prolonged heating is required to obtain roux having the desired taste and flavor. Moreover, in such cases, the heating of the roux in the middle of the kettle is particularly insufficient. This problem cannot be completely solved even if the starting material is sufficiently agitated in an kettle provided with blades for agitation. Thus, the quality of the resultant roux varies widely. The foregoing problem becomes more severe as the viscosity of the roux increases. In addition to the above problems, when roux is heated by such a roasting kettle, other problems also arise regarding, for example, energy cost, worker's safety and health.